Method and apparatus of high-speed manufacture of flap glued lined envelope



United States Patent Inventor Emerick .l. Mittermayer Norridge, Ill.

App]. No. 707.563

Filed Feb. 23, 1968 Patented Dec. 29, 1970 Assignee American Envelope Company a corporation of Illinois METHOD AND APPARATUS OF HIGH-SPEED MANUFACTURE OF FLAP GLUED LINED ENVELOPE 16 Claims, 11 Drawing Figs.

Int. Cl. B31'b 1/08 Field ofSearch 93/61, 61A,

2 3K21 owl 6/14: 530129 Primary Examiner-Bernard Stickney Attorne vMann, Brown, McWilliams & Bradway ABSTRACT: An envelope manufacturing machine utilizing a drum with suction ports to transfer blanks from a separator station past a liner-applying unit and to scoring, folding and gluing stations. The liner is glued to the blank only at the flap portion of the blank. A liner transfer element utilizes air pres sure to force the unglued portion of the liner against the blank and transfer belts remove the assembled blank and liner from the drum and pass them to the scoring, folding and gluing stations. Mechanism moves a gumming unit out of contact in relation with the drum in the absence of a blank on the drum.

PATENTED nE-c2 919m SHEET 1. 0F 4 PATENTED nEczs I970 cjgffya METHOD AND APPARATUS OF HIGH-SPEED MANUFACTURE OF FLAP GLUED LINED ENVELOPE The present invention is directed to new and useful improvements in envelope manufacturing machines and is particularly concerned with improvements which facilitate the placement of liners on the envelope blanks in a neat fashion.

In many cases it is desirable to provide liners for the flap portion and interior of envelopes. If the liner is glued entirely to the body of the envelope blank, a wrinkle often occurs (particularly in the case of relatively heavy papers) because of the two layers comprised of the liner and envelope blank. Because of this, it has heretofore been proposed to glue the flap portion of the liner only to the flap of the envelope blank, thus leaving the remaining body portion of the liner unglued with respect to the main body portion of the envelope. Lined envelopes of this type have heretofore been produced on plunger-type envelope machines but the plunger-type machines have relatively slow production speeds as compared with other types of machines, particularly those of the type in which envelope blanks are continuously conveyed past liner placement, scoring, folding and gluing stations at high speeds. If the liner is glued to the flap portion only of the blank in this type of machine, the unglued main body portion-of the blank is at the leading edge of the envelope blank and thus tends to be raised from the envelope blank by air currents. When this happens, the liner becomes torn or wrinkled and the envelope is then unsatisfactory.

The present invention has as its principal purpose the modification of the continuously operating types of machines in a manner such that liners may be affixed to the flap portions of envelope blanks only and at speeds some two or three times faster than that of the plunger machines.

A related purpose of the invention is to improve thetransfer of envelope blanks from the separating station to scoring, folding and gluing stations.

A further related purpose of the invention is to improve glue-applying facilities in a machine of this general class to minimize the undesired placement of glue on a transfer drum.

These and other other purposes of the invention will become more apparent in the course of the ensuing specification when taken in connection with the accompanying drawings, in which:

FIG. I is a diagrammatic assembly view illustrating the principles of the invention as applied to an envelope manufacturing machine;

FIG. 2 is an end view of a cylinder or drum illustrated in FIG. 1;

FIG. 3 is a side view of a mounting assembly for a gum-applying roller utilized in the machine of FIG. 1;

FIG. 4 is a sectional view of one valve assembly utilized in the machine of FIG. 1;

FIGS. 5, 6, 7 and 8 are detailed views of valve elements utilized in another valve assembly for the machine of FIG. 1;

FIG. 9 is a plan view of a lined envelope produced in accordance with the principles of the present invention;

FIG. 10 is an enlarged view of a portion of the mechanism shown in FIG. 1; and

FIG. 11 is a diagrammatic view of a control unit utilized in FIG. 1.

Referring specifically now to the drawings, wherein like characters designate like elements throughout, and in the first instance to FIG. I. the numeral generally designates a conveying chain or the like which is adapted to continuously convey envelope blanks toward a separator diagrammatically represented at 21. The blanks conveyed by the chain 20 are in overlapped relation as represented at 22 and are separated at the separating station 21 to a spaced relation for conveying along chain or belt 23 as is diagrammatically represented at 24. The conveying chain 20 is a conventional apparatus of this type as is the separating station 21. It should be understood that suitable facilities are utilized to feed envelope blanks to the conveyor chain 20 which in turn feeds them in the relation indicated at 22 to the separator station-21.

A sensing microswitch 23a has a "feeler" arm which is spring biased against the blanks B and is closed whenever arm 23b is not in contact with a blank B for a purpose which will be pointed out in subsequent portions of this specification.

The conveyor 23 delivers the envelope blanks in the spaced relation indicated at 24 to a drum or cylinder 25. The drum or cylinder 25 includes suction ports which pick up the envelope blanks from the conveyor 23, conveys them past a gum or adhesive applying roller assembly generally designated at 26, and then past a superimposed liner unit generally designated at 27 wherein a liner is applied to the blank in the proper registering relation. The liner unit includes a movable sucker arm 27a which withdraws liners one at a time from a stack of liners 27b and delivers the liners to the envelope blanks as disclosed in my copending application, Ser. No. 549,299, filed May I1, 1966, now U.S. Pat. No. 3,380,353. Then the blank is delivered to a conveying belt 28 which in turn passes the assembled envelope blank and liner to a scoring and then a folding and gluing station as diagrammatically indicated by the arrows in FIG. 1.

It should be understood that the drum 25, conveyors, adhesive applying assembly and liner unit 27 are suitably supported in the framework of the machine, which is not illustrated in the drawings. It should be understood that the principles of the invention may be applied to existing high-speed continuous envelope manufacturing machines by incorporating the principles disclosed herein in existing machines.

The drum 25 has apertures therein at spaced intervals in the drum corresponding to the spacing of the envelope blanks delivered there by the conveyor 23. For example, as illustrated in FIG. 1, the drum has five groups of apertures therein and each group is spaced from an adjacent group by the spacing of the envelope blanks on the conveyor 23. The drum 25 is rotated in synchronized relation to the speed of the conveyor 23 so that an envelope blank is positioned at the delivery end 29 of the conveyor 23 at the time that a group of apertures is opposed thereto so that suction applied to the apertures may pick up an envelope blank from the conveyor 23. As illustrated in the drawings, each group of apertures is carried in a removable plate 30 which is positioned in the drum. It should be understood that the apertures need not be carried in removable plates and can be formed simply by drilling through the drum. The use of removable plates as illustrated is convenient in that it permits the selective use of different plates with apertures therein positioned at different locations in different plates so that different plates accommodate different sizes and styles of envelope blanks. In lieu of using removable plates, apertures may be variantly disposed in the drum and apertures not desired for use in the manufacture of any particular type of envelope may be simply covered with masking tape.

As illustrated in the drawings, each group of apertures consists of two rows of apertures as designated at 31 and 32. These apertures are positioned so that they extend across the leading and trailing portions of an envelope blank as is illustrated in FIG. 2. Each group of apertures is connected by means of conduits 33 with a valve assembly generally designated at 34. Valve assembly 34 is positioned generally coaxially with the supporting shaft 35 of the drum. The drum 25 may have the customary radially extending supporting webs 36 (shown in dotted outline) leading from the wall of the drum to the supporting hub therefor.

The valve assembly 34, as illustrated in FIGS. 5-8 inclusive, includes a stationary manifold member 37 and a rotatable port plate 38 alongside member 37. The stationary manifold member is generally cylindrical in form and includes an inlet line 39 which leads to a center passage 40 therein. An arcuate passage 41 is in communication with the central passage 40. Passage 41 is formed in the face of the member 37 which is opposed to the face of the porting member 38. The port plate 38 has groups of ports 42 in the face thereof in position to traverse the arcuate passage 41 during rotation of the rotatable port plate. Each group of ports 42 includes two ports. One port of each group leads to the forward series of apertures 31 in the wall of the drum while the other communicates through its associated conduit 33 with the trailing row of apertures 32 in the drum.

Suitable bearing means 43 may be carried by the rotatable port plate and the stationary manifold 37 so as to minimize friction between the port plate and the manifold 37 during rotation of the rotatable port plate. Suitable means may be utilized to seal the two elements together so that when conduit 39 is connected to a source of vacuum and during rotation of the shaft 35 and rotatable port 38, the suction is adequately established to the apertures 31 and 32.

The length and position of the arcuate passage 31 is such that suction is applied to the leading row of apertures 31 in the drum just prior to the time that it becomes opposed to an envelope blank in position on conveyor 23 to be picked up therefrom, while the suction is terminated at or near the point designated at A in the drawings so that the envelope blank may be released from the drum at this point. As is illustrated in the drawings, the arcuate passage 41 extends for an are greater than 180 which in turn a corresponds with the arc traversed by the drum from the pickup point generally designated at 29 to the release point designated at A. As one of the ports in the rotatable port plate first comes into overlapping relation with one end of the arcuate passage 41, suction is established with that port and with the drum apertures communicating with that port, and this communication continues during rotation of the rotatable port plate until the particular port 42 passes the other end of the passage 41 whereupon communication is blocked by the solid face of the stationary manifold member until that particular port again reaches the end of the passage 41.

The amount of suction or vacuum forces supplied to the apertures may be varied as long as it is enough to hold the blanks on the drum 25. I

The unit may optionally include the use of belts 44 (FIG. 2) which may be positioned at the right side of the drum illustrated in FIG. 1 and assist in holding envelope blanks against the surface of the drum for a portion of their travel.

The adhesive-applying unit is positioned at one side of the drum so as to apply adhesive to the trailing or flap side of envelope blanks prior to the time that a liner is transferred to the blank by the liner unit 27. As is illustrated, the adhesive-applying unit includes an applying roller 45 carried by a shaft 46 and driven in timed synchronized relation with the drum, and a transfer roller 46a for transferring adhesive from a reservoir 48 to the applying roller 45. A microswitch 47 is positioned generally centrally of the drum and has a finger which is biased by light spring pressure against an envelope blank as designated at B in FIG. 2. The spring pressure on this finger may cause it to drop into a shallow groove 48 which is machined in the periphery of the drum whenever an envelope blank is not in a position tohold the finger out of the groove. Switch 47 is adapted to close whenever the finger 47a drops into the groove 48 and close a circuit to a solenoid 49. This circuit includes an on-off commutator element 47b which is operated in synchronism with the rotation of drum 25 so that the circuit is disabled during the time that the vacant drum space between blanks is opposed to roller 45. In other words, the power circuit is activated by the commutator when the envelope blank carrying space of the drum is opposed to roller 45 and disabled when the space of the drum between the envelope blank carrying spaces is opposed to roller 45. Even though the circuit is activated, power is not supplied to solenoid 49 unless switch 47 is also closed, as when the envelopecarrying space is vacant. Switch 47 closes every time the drum space between blanks passes the switch, but this is of no consequence since the commutator has disabled the circuit during those times.

The shaft 46 of the adhesive-applying roller is mounted in bearing blocks 50 which are slidably mounted in the frame 51 of the machine as illustrated in FIG. 3. A spring 52 biases the bearing 50 in its guideway toward a normal position as illustrated in FIG. 3 and in this position the shaft of the transfer roller 26 is positioned to apply adhesive to the flap portion of the envelope blank on the trailing edge of the blank as it progresses toward the liner unit. Whenever solenoid 49 is energized, a connecting linkage 53 forces shaft 46 upwardly in its guideway and to the left as illustrated in FIG. 3 which is in the direction of the arrow designated at C in FIG. 1. This removes the roller 45 from contact with both the drum and the transfer roller 46a and, when so removed, adhesive is notw transferred to roller 45, nor is adhesive transferred from roller 45 to the drum. This prevents the application of adhesive to the drum whenever an envelope blank is not positioned to receive such adhesive.

The liner unit 27 includes a liner transfer element 53 which is rotatable with a hollow shaft 54. The liner-applying unit may be of the precise type illustrated in my copending application, Ser. No. 549,299, filed in the US. Patent Office on May ll, I966, incorporated herein by reference, with modification of the transfer element-which is represented. at in the drawings of that application. The transfer element 53 is adapted to pick up envelope liners from other elements of the liner unit and deliver them to the envelope blank carried by the surface of the drum. The pressure engagement between the element 53 and the surface of the drum presses the trailing portion of the liner against the trailing or fiap portion of the envelope blank so as to bond the liner to the envelope blank at the flap portion thereof. As shown, the element 53 is formed as an arcuate segment rotatable with shaft 54 about the axis thereof. It is advantageous to form the segment 53 in two sections, namely a front section 53a which carries the suction and pressure passages 56, and a trailing section 5312 which is made of an elastomeric material. The diameter of the section 53b of elastomeric material may be made slightly greater than the diameter of the section 53a so that the section 5311 performs the function of firmly pressing the flap portion of the liner against the adhesive on the flap of the envelope blank. The

length of the arcuate segment may be increased by adding a shoe 55a to the trailing portion thereof if desired.

Transfer element 53 includes a front series of apertures 55 formed therein and a rear series of apertures 56 all as disclosed in my aforesaid copending application. These rows of apertures communicate with the hollow interior of the shaft 54 and are adapted to be connected to a source of vacuum and then to a source of pressure through a valve element designated at 57. The valve element is illustrated particularly in FIG. 4. As illustrated in FIG. 4, the hollow shaft 54 has a rotatable hub 58 fixed thereto and with a port 59 formed therein. The hub portion 58 is received within a recess 60 in a stationary valve block 61. Suitable means (not shown) support valve block 61. Valve block 61 has an arcuate passage 62 formed therein through an arc of in excess of and a second arcuate passage 63 formed therein for a relative minor are which may be on the order of 3045. The passage 62 is connected to a source of suction by means of the coupling fitting 64 while. the passage 63 is connected to a source of pressure through the coupling fitting 65. During rotation of the shaft 54 and in a counterclockwise direction as illustrated in FIG. 4, which would be clockwise rotation in FIG. 1, the port 59 which communicates with the shaft interior and thus with the apertures 55 and 56, first traverses the suction passage 62. This is immediately prior to the time that an en.- velope liner is transferred to the element 53 in the unit 27. The suction may begin, for example, at approximately the point marked 5 in FIG. 1 and the suction to the liner-applying element is maintained so as to hold the liner on the element until the liner reaches the point generally designated at A in FIGS. 1 and 10 which is the point of pressure engagement between the liner-applying element 53 and drum 25. The pressure engagement forces the liner positively against the surface of th envelope blank.

As the timed, synchronized movement of the drum and element 53 continue in a feeding direction towards conveyor 28,

pressure is applied through the apertures 55 and 56 by reasonv of the port 59 coming in communication with the passage 63 and this pressure continues until the apertures 55 and 56 are in approximately the position illustrated in FIG. I. This pressure is directed against the leading edge of the liners and forces the liner against the body of the envelope blank. This prevents the unglued leading edge of the liner from rising up due to air currents or the like.

It should be noted in FIG. 1 that this air pressure is directed against the blank as it is passing over the fill-in plate or shoe 67 over which the blank rides as it is removed from the drum and delivered to the conveyor belt 28. The shoe or plate 67 may include small wirelike fingers 670 that ride in grooves 67b and 670 of the drum as seen in FIGS. 2 and so that these wirelike fingers are positively inserted beneath the envelope blank and as the blank passes over these fingers it progresses smoothly over the plate 67 to the conveyor 28.

The amount of suction or vacuum forces and pressure forces may be varied as long as the vacuum is sufiicient to hold the liner on the transfer element and the pressure is sufficient to hold the liner tight against the blank.

The conveyor 28 includes upper and lower superimposed belts 68 and 69 which are positioned to securely grip the assembled envelope blank and liner along the central portion thereof and to transfer them to a further conveyor 70 for transfer to the scoring station and folding and gluing stations.

The upper belt may be extended beyond the lower belt toward the transfer element 53 as is seen in the drawings. In lieu of this, the right-hand belt supporting pulley for belt 69 may be vertically aligned with the belt supporting pulley for belt 68, and one or more rollers may be positioned between the end of the upper belt and the transfer element 53 so as to hold the blanks against the fill-in plate 67. The pulse of air from the element 53 is nonetheless used. The important thing is that the pulse of air hold the liner on the blank until at or shortly before the time that the liner passes beneath the upper belt or the first roller, if one or more rollers is used. The inclination of the pressure passage causes the air to be deflected toward the holddown belts. This helps to keep the liner flat against the blank.

A series of pressure rollers 71 are positioned along the entire lower reach of the upper belt 69 and are spring biased as by means of springs 72 against thelower reach of the belt. It should be understood that some of the rollers 71 have been omitted in FIG. 1 for purposes of clarity. As the assembled en- I velope blank and liner pass the conveyor belts 68 and 69, they are fed to a further conveyor 70 which has a series of holddown springlike elements 73 of conventional construction in machines of this class. The holddown reeds or springs in this a particular invention are positioned to engage the outside of the envelope blank so as not to interfere with the flap of the envelope.

Switch 23a, which is closed whenever an envelope blank is not properly positioned beneath the actuating arm 23b, is included in a circuit leading to a solenoid 75 which, when energized, closes a valve 76 which supplies vacuum through line 77 to the sucker arm 27a of the liner unit. A conduit 78 is adapted to communicate a suitable source of vacuum through the valve 76 with the line 77. The energizing circuit for the solenoid 75 also includes a commutator element 79 which is driven in timed synchronized relation to the movement of the envelope blanks along the conveyor 23. It is driven so as to close the power line to switch 23a whenever a blank passes the actuating arm 23b and maintains the circuit to switch 23a for a .time interval corresponding to the time of passage of a blank underneath arm 23b. The commutator element 79 opens the power line to switch 23a for a time interval corresponding to the time that the space between properly spaced envelope blanks, during normal operation, is opposed to the actuating arm 23b. The circuit may be placed across the power lines for the main operating motor of the machine, as may the circuit for the gum-applying unit 26. Commutator 79 activates the circuit to the solenoid 75 whenever a blank should be beneath actuating arm or sensing arm 23b and deactivates the circuit during those times that the spaces between blanks are beneath arm 23b. Then, if an envelope blank is not in proper position along the reach of the conveyor 23, arm 23b drops to close switch 230 and at this time the commutator has activated the circuit so that solenoid 75 is energized to close valve 76 and shut off the supply of vacuum to the sucker arm 27a. This stops the feed of liners to the element 53 and avoids waste of liners. It is advantageous to position the microswitch 23a at such a position along the conveyor 23 that the supply of liners to element 53 is stopped just prior to the time that an envelope blank carrying space (without the usual envelope blank thereon) of the drum passes beneath the transfer element 53. In this regard, the liner unit may be built so that two or more liners are in the process of transfer between the sucker arm 27b and the transfer element 53 before they ever reach the transfer element 53. Hence, it is advantageous to position the microswitch 23a along the reach of conveyor 23 at such a position that the suction to the sucker arm 27a is stopped at the proper time. It should be understood that the showing of the circuit is diagrammatic and that the overall circuit used may include other elements.

By reason of fixing the liner to the flap portion of the envelope only, as designated by the glue area designated at 74 in FIG. 9, the blank may be folded along the line 75 between the body of the envelope and the flap portion thereof repeatedly without causing any wrinkling of the assembled envelope, which wrinkling occurs if the entire liner is glued to the body of the envelope.

In operation, envelope blanks are fed to the conveyor chain in overlapped relation by a blank feeding mechanism of a type known to the art. The blanks then pass the separator station 21 where the blanks are separated from one another and staggered along the conveyor 23. The chain then passes the staggered blanks against the surface of the drum 25. The apertures in the drum opposed to the blank are then in communication with the source of vacuum and the blanks are held firmly against the surface of the drum. As the drum rotates it carries the blanks on the surface thereof past the gumming station wherein the gumming roller applies glue to the flap portion of the envelope and in a position for the liner. The blank then passes beneath the liner unit where the transfer element 5 3 of the liner unit positions a liner L in registering relation to the envelope blank B (see FIG. 10) and with the trailing edge of the liner fixed against the flap of the envelope blank. The remainder of the flap loosely overlies the main body of the blank. Immediately after the placement of the liner on the blank, the source of suction in the transfer element is terminated and this is followed by a pulse of positive air pressure which forces the unglued portion of the liner neatly against the main body portion of the blank. The suction in the drum is also terminated at about point A. The suction in the drum may be continued for a short time after passing point A. In the case of lightweight papers, the suction in the drum may then help to hold the liner on the blank.

With the suction forces removed from the drum, the fill-in plate 67 picks the blank and liner from the surface of the drum and the blank is fed between the opposed transfer belts. These belts engage the medial portion of the assembled blank and liner and hold the liner firmly against the blank. These belts then transfer the assembled blank and liner to the scoring station where the metallic reeds or springs hold the blank in flat position. It may be noted that the reeds or springs engage only the portions of the envelope blank outside of the liner and thus the holddown reeds do not contact the liner. The assembled blank and liner then passes to the folding and gluing station wherein conventional mechanism folds and glues the envelope in conventional fashion.

By reason of the sensing means, the gummer is moved out of contact with the drum and transfer roll whenever the microswitch detects the absence of an envelope blank on the drum. Thus, glue is not deposited on the drum if any envelope blank is not in position to receive it, and shutdown time for this reason is unnecessary.

The use of the blank-sensing microswitch 23a adequately stops the feed of envelope liners to avoid wasting liners.

Whereas l have shown and described an operative form of the invention, it should be understood that this showing and description thereof should be taken in an illustrative or diagrammatic sense only. There are modifications to the invention which will fall within the scope and spirit thereof and which will be apparent to those skilled in the art. The scope of the invention should be measured only by the scope of the hereinafter appended claims.

lclaim:

1. in an envelope manufacturing machine, a cylindrical drum, means for rotating said drum, means for feeding envelope blanks in spaced relation to said drum, said drum having a plurality of apertures in the cylindrical surface thereof, means for connecting said apertures to a source of vacuum whereby blanks fed against the surface of said drum are held against said drum by the vacuum forces produced in said apertures, means for picking envelope blanks from the surface of said drum and for delivering said blanks to scoring and folding mechanism, means for disconnecting said source of vacuum from said apertures immediately prior to the time that said pickoff means removes said blanks from said drum, a liner feeding unit positioned above said drum for feeding envelope liners in timed relation to the movement of envelope blanks on said drum so as to deposit liners in registering relation on said blanks, and means adjacent said drum for applying glue to said blanks prior to the time that the blanks are carried into opposed relation to said liner unit, said liner unit including a rotatable transfer element movable in synchronized relation to the rotation of said drum, and suction means carried by said element for holding the liners on said element until a liner is aligned and deposited on an envelope blank carried by said drum.

2. In an envelope manufacturing machine, means for feeding envelope blanks in spaced relation along a path, a liner feeding unit positioned above said path for feeding envelope liners in timed relation to the movement of envelope blanks along said path so as to deposit a liner in registering relation on each of said blanks, said liner unit including a rotatable transfer element movable in synchronized relation to the movement of said blanks, means cooperable with said element for pressing each liner against a blank, suction means carried by said element for holding the liner on said element until the liner is aligned and pressed against an envelope blank moving along said path, and air pressure means carried by said element for applying a pulse of air pressure to the leading portion of said liner after said element has deposited said liner on said envelope blank in registering relation.

3. The structure of claim 2 wherein said feeding means and said cooperable means are defined by a rotatable drum.

4. In an envelope-manufacturing machine, means for feeding envelope blanks in spaced relation along a path, a liner feeding unit positioned alongside said path for feeding envelope liners in timed relation to the movement of the envelope blanks so as to deposit liners in registering relation on said blanks, means adjacent said path for applying glue to the flap portions of said blanks prior to the time that the blanks are carried into opposed relation to said liner unit, said liner unit including a rotatable transfer element, said element having a plurality of air ports therein communicating with a fluid passage; means for connecting said passage to a source of suction to thereby hold liners on said element as they are transferred from the liner unit to an envelope blank in registering relatiomi means for blocking the suction connection when said liner has been positioned on an envelope blank, and means for immediately thereafter connecting said conduit to a source of positive fluid pressure whereby said liner is forced by said pressure against the envelope blank.

5. The structure of claim 4 wherein said element is rotatable with a hollow shaft communicating with said apertures and the interior of said shaft is in communication with a valve at one end thereof, said valve including a stationary member with a first passage connected to a source of vacuum and a second passage connected to a source of pressure, a rotatable member carried with said hollow shaft and in communication with the interior thereof, said member beingpositioned for rotation in. said stationary member, said rotatable member having a passage communication with the interior of said shaft and communicating successively with said suction passage and said pressure passage during rotation of said member.

6. The structure of claim 4 characterized by and including blank pickoff means for transferring blanks from said feeding means including means for holdingsaid liner against said blank and for transferring the assembled blank and liner to scoring and folding stations.

7. The structure of claim 6 wherein said last names. means includes a pair of overlapping belts for gripping assembled liners and blanks therebetween for transferring the assembled liner and blank to scoring and folding stations.

8. The structure of claim 4 characterized by and including means for sensing the presence of envelope blanks in proper spacedrelation as they move along said path and prior to the placement of a liner on the blanks, and said liner unit including a movable sucker arm for removing liners one at a time from a stack of liners, and means for deactivating said sucker arm in response to the absence of an envelope blank in proper spaced relation along said path.

9. The structure of claim 8 wherein said sensing means includes a switch having an actuating element for detecting the presence and absence of envelope blanks in said path, and said deactivating means includes a solenoid valve in a line communicating a source of vacuum to said sucker arm so that said sucker arm removes liners by suction forces, an energizing circuit for said solenoid valve including said switch, and a commutator element for deactivating said circuit in timed relation to the movement of envelope blanks along said path and whenever a space between properly spaced envelope blanks passes said sensing switch.

10. The method of applying liners'to envelope blanks while adhesively affixing only the flap of the envelope blank to the liner and while a blank progresses through a path of movement with the flap of the blank at the trailing edgeof the 7 blank, including the steps of feeding an envelope liner to a point of pressure engagement with and in proper registering relation to an envelope blank as a blank progresses along a path of movement, said blank having adhesive on the flap thereof so that a liner may be affixed only to the flap of the blank while the remainder of the liner loosely overlies other portions of said blank, pressing the envelope liner against the adhesively coated flap of the envelope blank during such movement, continuing the movement of the envelope blank from the position of pressure engagement to conveying facilities, and directing a source of pressure against the leading portion of the liner after the leading portion of the liner passes the point of pressure engagement and just prior to the time that the envelope blank moves to said additional conveying facilities.

11. The method set forth in claim 10 wherein said envelope liner is fed to said point of pressure engagement with a vacuum applying member and the suction is terminated at about the time of pressure engagement between said envelope liner and envelope blank and said member is then used to direct said pressure against the leading portion of the envelope liner.

12. in an envelope manufacturing machine, means for feeding envelope blanks in spaced relation along a path, a liner feeding unit positioned alongside said path for feeding envelope liners in timed relation to the movement of the envelope blanks so as to deposit liners in registering relation on said blanks, means adjacent said path for applying glue to the blanks prior to the time that the blanks are carried into opposed relation to said liner unit, said liner unit including a rotatable transfer element for transferring liners in registering relation to said blanks as they move along said path, said liner unit including a movable sucker arm for remo ing liners one at a time from a stack of liners and means for transferring liners from said sucker arm to said rotatable transfer element, means for sensing the presence of envelope blanks in proper spaced relation as they move along said path and prior to the placement of liners on said blanks, and means operated by said sensing means for rendering said sucker arm ineffective to remove liners from said stack in response to the absence of an envelope blank in proper spaced relation in said path at a position upstream of said liner unit.

13. The structure of claim 1 characterized by and including a glue-applying unit positioned adjacent the periphery of said drum at a location such that the envelope blanks carried by said drum pass said glue-applying unit prior to the time that they are released from said drum.

14. The structure of claim 13 wherein said glue-applying unit includes first roller means for transferring glue from a second roller to an envelope blank carried by said drum, said first roller means being movably mounted adjacent said drum for movement against said drum and said second roller and to a second position spaced therefrom, switch means for sensing the absence of an envelope blank on said drum, and means operated by said switch means for moving said first roller means to said second position in response to the absence of an envelope blank on said drum.

15. The structure of claim 14 wherein said last named means includes an electrical power element for moving said roller means and an energizing circuit therefor, said energizing circuit including means for alternately activating and disabling the circuit in timed relation to the movement of article-carrying spaces and vacant spaces between articles on said drum. respectively, said switch means being effective to complete the circuit to said power element when said circuit is activated and when an article-carrying space of said drum is vacant.

16. in an envelope manufacturing machine, means for feeding envelope blanks in spaced relation along a path, a liner feeding unit positioned above said path for feeding envelope liners in timed relation to the movement of envelope blanks along said path so as to deposit a liner in registering relation on each of said blanks, said liner unit including a rotatable transfer element movable in synchronized relation to the movement of said blanks, means cooperable with said element for pressing each liner against a blank, suction means carried by said element for holding the liner on said element until the liner is aligned and pressed against an envelope blank moving along said path. and positive means cooperable with the leading portion of a liner for holding the leading portion of said liner against said blank, said means being effective immediately after said suction means presses a liner against an envelope blank moving along said path. 

